The mounting of tubeless tires on wheels by automobile manufacturers is normally accomplished by a high production apparatus where a wheel is placed on a conveyer, a tire is preliminarily positioned relative to the wheel, and as the wheel and tire are conveyed from station to station, the tire is soaped, the tire is forced over the wheel rim and mounted intermediate to the wheel rims, the wheel and tire can be rotated relative to each other in accordance with previously applied reference points, and the tire is inflated to a predetermined pressure.
To reduce the duration of time required for inflation it is a common practice to impose an annular axial force on one of the tire sidewalls which causes the other tire sidewall bead to seat against the associated wheel rim while the deflected sidewall bead is displaced from its associated wheel rim. Consequently, an inflation chamber is defined by the engaging apparatus and compressed air is forced into the tire around the displaced sidewall bead, and after the desired pressurizing is accomplished the deflected tire sidewall is permitted to expand to seat its bead against the wheel rim to maintain the inflation pressure, and such inflation can be readily accomplished in a very short time.
With higher production tire inflation devices of this type, an annular inflation chamber is defined which includes the interior of the tire wherein pressurization of the chamber produces the desired pressure within the tire. To define the inflation chamber, an annular wheel seal is usually employed which engages the wheel rim. Further, an annular tire sidewall seal is normally employed which engages the tire sidewall for displacing the sidewall, and also defining the pressurized chamber. The sidewall engaging seal and the wheel rim engaging apparatus are displaceable with respect to each other to produce the desired sequence of operation. No sealing apparatus is associated with the opposite side of the tire, since the seal is achieved by engagement of the tire bead with the wheel rim. Examples of the described tire inflation apparatus can be seen in U.S. Pat. No. 4,183,392 and U.S. Pat. No. 4,735,250.
There are several disadvantages inherent in high production tire inflation devices of the type described above. One serious problem occurs at the interface between the sidewall of the tire carcass and the annular tire sidewall seal when the tire carcass is deformed in a non-uniform manner. In order for an effective seal to occur between the displaced tire sidewall of the carcass and the associated annular tire sidewall seal engaging the carcass, the annular inflation chamber structure must be lowered sufficiently to sealingly engage the annular tire sidewall seal with the lowest level of the distorted tire carcass sidewall. In the past, the annular inflation chamber, or inflation head, was held in a fixed orientation as it was moved with respect to the tire sidewall for sealing engagement therewith. In addition, structural limitations were present in limiting the extent to which the annular tire sidewall seal could move relative to the position of the annular wheel seal engagement with the wheel rim in order to define the inflation chamber. In instances where excessive distortion of the tire carcass was present, an insufficient seal was provided between the annular tire sidewall seal due to incomplete or non-sealing engagement with the tire sidewall. Excessively distorted tire carcasses passing through the production line undesirably impacts the high production tire inflation apparatus, leading to unproductive down time or defective, non-inflated tire carcass and wheel combinations. The tire carcass distortion can be due to deformation arising from tire banding, temperature, design, or other reasons, such as an excessive gap or clearance that may exist between the uninflated tire sidewall bead and the rim which defies closing even when the fixed orientation inflation head is moved to the furthest extent of movement of the annular tire sidewall seal in previously known devices. When an ineffective seal is created, pressurization of the inflation apparatus causes considerable air to be lost because of the misfit between the tire sidewall and the associated annular sidewall seal. Consequently, high noise levels can be created due to the escape of large quantities of high pressure air, and if a seal cannot be established with the tire, the tire will not inflate and must be recycled or remounted to produce the required seal necessary for inflation.